1. Field of the Invention
The present invention broadly relates to the effects of air turbulence around a high energy laser turret on a high energy laser beam and, more particularly, is concerned with apparatus which applies interferometric techniques to obtain information useful in predicting the degradation of such a beam when it passes through turret induced turbulence.
2. Description of the Prior Art
All types of systems which transmit a coherent optical beam through the earth's atmosphere suffers from distortion caused by the passage of the beam through the atmosphere. More particularly, turbulence in the atmosphere distorts the wavefronts of the optical energy in the beam so that they do not arrive at a remote location as parallel straight lines. This results in the power illuminating a given remote target being reduced.
Similarly, a high energy optical beam generated by a laser on a moving aircraft is affected by the turbulence created by the aircraft. Consequently, it would be desirable to devise some means for gathering data which will be useful in predicting high energy laser performance from airborne platforms in the presence of the turbulence generated as the aircraft moves through the atmosphere. Patents to Brooks, U.S. Pat. No. 3,567,324; and Misek, U.S. Pat. No. 4,210,400 indicate that systems incorporating interferometric techniques have been devised to measure the effects of turbulence on laser-generated energy beams. However, these systems appear to involve laser beam transmissions between stations separated by long distances or between a flying aircraft and a fixed ground station. While these prior art systems may satisfactorily perform their intended functions in the specific applications for which they were designed, a need exists for a measurement apparatus which provides information specifically on the turbulence generated by a high energy laser turret as it moves through the atmosphere.